Automatic conveyors systems are used to convey or route articles between work stations, or other locations, and in many conveyor systems it is desirable to move the articles from one vertical level to another. Frequently, inclined endless belt or cleat conveyors are employed to move articles between different vertical layers, but the inclined conveyor, due to the fact that it must operate at a relatively gradual slope, requires substantial floor space.
Vertical type elevators have also been employed in the past to move articles between different levels in a conveying system. In one common form of elevator, a chain is carried by a pair of vertically disposed sprockets and a series of rigid platforms extend outwardly at intervals throughout the length of the chain. As the chain moves in its upward vertical run, articles to be conveyed are introduced onto the platform at a lower level and the articles are subsequently removed from the platforms at an upper level in the vertical run. While elevators of this type require less floor space than inclined conveyors, it is necessary in the conventional vertical elevator to momentarily stop operation of the elevator in order that the article can be removed from the platform or carrier and delivered to an adjacent conveyor.